proton mail

Claws Mail is a GTK+ based, lightweight, and fast e-mail client and newsreader.

The world's first "Real-Time" e-mail scanner for Mail Server.

Fully-featured SMTP/POP3 mail server program to use along with any mail client.

Allow you to recover deleted emails from Windows Mail and Live Mail.

The e-Capsule Private Mail is a family of "zero-footprint" secure e-mail clients

It is designed to directly search e-mail addresses from mail servers.

Opt-In Mail is a small application to send e-mail.

Softalk Mail Server is a fully featured mail server.

Vivian Mail - A free mail client for SMTP and POP3-Server.

Smart Mail Notifier is a tiny user friendly software for checking mail and RSS